1. Field of the Invention
Embodiments of the invention relate to intake screen assemblies.
2. Description of the Related Art
Water collection systems are typically used to provide water to end users such as manufacturing plants, cities, irrigation systems, and power generation facilities located adjacent a body of water such as a river, lake, or salt water bodies. The end users may employ this type of system as an alternative to drilling water well or buying water from a municipality. Additionally, use of these systems may be determined by the location of the end user, for example remote locations where water from a municipal source and/or electrical power to operate pumps is not readily available. These water collection systems have the ability to adapt to varying conditions and deliver water efficiently and economically.
These water collection systems typically use an inlet pipe adapted to transport water from a position submerged in a body of water to the end user adjacent the body of water. An inlet pipe is submerged in the body of water and the end of the inlet pipe is typically coupled to an intake screen assembly which typically has a plurality of filtering members. The filtering members are configured to prevent waterborne debris and aquatic life, of a certain size, from entering the inlet pipe.
A common intake screen assembly generally comprises large cylindrical screens with a closure on one end and a pipe connection on the other end. A typical construction for large intake screen assemblies is a flanged tee section with two screen cylinders that are cantilevered from opposite ends of the tee section, and with solid closures such as flat plates, cones, or dished heads on the distal ends of each screen cylinder. The separate components of the assemblies are usually welded together.
The material used to fabricate the separate components is generally stainless steel. However, where certain aquatic animals, such as zebra mussels, are present the preferred material is a copper-nickel alloy. Since copper-nickel alloys are more expensive than stainless steel, it is preferred to supply a hybrid assembly where only the cylindrical screen portion is formed from copper-nickel and the remainder of the assembly is formed from stainless steel.
Traditionally the hybrid assembly has been accomplished by fabricating a copper-nickel cylindrical screen and bolting it the rest of the stainless steel components. There are two potential problems with the hybrid assembly. First, in high loading situations, significant reinforcement of the cylindrical screen is required since the copper-nickel material is not as strong as the stainless steel material. The reinforcing must be designed to transfer through the bolts, which may increase the cost and complexity of manufacture. Second, the cylindrical screen must be bolted to the stainless steel components using gaskets and isolation sleeves to prevent contact of the two dissimilar metals, thereby preventing galvanic corrosion. These additional corrosion protection measures may also increase the cost and complexity of manufacture.
Therefore, there is a need for new and improved hybrid intake screen assemblies.